The Palazzo Chigi is the largest secular building in San Quirico d'Orcia, a 17th-century palace built for the powerful Chigi family of Siena who became the dominant local landowners. The facade is severe and impressive for a small Tuscan hill town, evidence of the wealth the Chigi clan accumulated through banking (one of them became Pope Alexander VII).
The building is not generally open to the public, but the exterior is worth a look as you walk the main street. It anchors the historic centre and gives a sense of the civic ambition that shaped the town in its prosperous 17th-century period.